How to get error message returned by DotNetOpenAuth.OAuth2 on client side?

Question

I\'m using ExchangeUserCredentialForToken function to get the token from the Authorization server. It\'s working fine when my user exists in my databas, but whe

Answer 1

Jeff's solution does not work for me, but when I use OnSendingHeaders it works fine:

public class InvalidAuthenticationMiddleware : OwinMiddleware
{
    public InvalidAuthenticationMiddleware(OwinMiddleware next) : base(next) { }

    public override async Task Invoke(IOwinContext context)
    {
        context.Response.OnSendingHeaders(state =>
        {
            var response = (OwinResponse)state;

            if (!response.Headers.ContainsKey("AuthorizationResponse") && response.StatusCode != 400) return;

            response.Headers.Remove("AuthorizationResponse");
            response.StatusCode = 401;

        }, context.Response);

        await Next.Invoke(context);
    }
}